From Destinypedia, the Destiny wiki
The Vex Network (also known as The Nexus) is a massive, trans-dimensional and trans-temporal supercomputer-like virtual network the Vex operates, hoping to incorporate it and themselves into the very fabric of the universe.
It is theorized that the Vault of Glass is a portion of this network designed specifically for this purpose. Sekrion and the Hezen Protective are the architects for transforming Venus into another node of this network, however, through the efforts of Guardians, this endeavour has been stunted and any further attempts from the Vex to restart it have been met with failure.
List of appearances